Replicated pools use a simple replication strategy in which each written object is copied, in full, to multiple OSDs within the cluster. The number of replicas can be increased (from the default of three) to bolster data resiliency, but will naturally consume more cluster storage space. The replica count is intended to be set at cluster deploy time.
For a charm that is written to use Ceph as its backend storage the following pertinent configuration options are available:
ceph-osd-replication-count: 3
pool-type: replicated
The values given above are the defaults.
There is nothing that needs to be done to enable the ‘replicated’ pool type. It is ready “out of the box”.